Background and Objectives: Pathogenic bacteria, such as Escherichia coli are dangerous for human population due to acquisition of resistance genes to beta-lactam antibiotics. This resistance is due to extended spectrum β lactamase (ESBL) genes, which are caused by plasmids, transposons, and/or mutation. The main cause of resistance to beta-lactam antibiotics is lactamase enzymes. In this study, the frequency of ESBL producing E. coli and molecular detection of CTX-M-1 gene, were investigated.

Methods:In this descriptive cross-sectional study, 58 E. coli samples isolated from patients with urinary tract infection, were identified using standard biochemical tests. Then, drug susceptibility test was performed using standard disk diffusion method (Kirby-Bauer). In the following, combined disk test was performed to identify ESBL producing strains among the resistant isolates. Plasmid DNA was extracted from ESBL-producing strains and CTX-M-1 genes were detected using PCR.

Results: Out of 58 E.coli strains, 28 strains (48.27%), were ESBLs producer, which in the molecular analysis, 20 strains (71.42%) had CTX-M-1 gene.

Conclusion: The results of the preset study is indicative of a high percentage of beta-lactamase resistance among E. coli strains. Considering the high percentage of antibiotic resistance, precise antibiogram testing is necessary in infections caused by ESBL-producing organisms.